From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACD22C433E0 for ; Thu, 9 Jul 2020 15:00:58 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7CCFC20720 for ; Thu, 9 Jul 2020 15:00:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="sXjsW/W8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7CCFC20720 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvdimm-bounces@lists.01.org Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 4010211427DBD; Thu, 9 Jul 2020 08:00:58 -0700 (PDT) Received-SPF: None (mailfrom) identity=mailfrom; client-ip=2001:8b0:10b:1236::1; helo=casper.infradead.org; envelope-from=batv+9909843fd9ad822e0971+6164+infradead.org+hch@casper.srs.infradead.org; receiver= Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id B57AC111FF49B for ; Thu, 9 Jul 2020 08:00:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=d6Fy1Ff8XKWJW7cdhpnfoPEQT8m7nn2QugrKA2y4BTE=; b=sXjsW/W8stofL0fSqv1devL9iA NF8pTtSu1pmMI2cx2Ezm5BoeofYSnPN6/rZYmpD+i2SwKMs8rbtY2EPcBcEn7LmzBMlRLH+HYv4ou IIiSGFJU8JQLbSCfDquQtv8nlD8xpYOQ1F33SWeREt+m+MKW2AS9lsim693P8pOA6Vn81rDU4U0pQ 5CL7N1SiSxz2S6PRS4eEqvntN+bK6HeL9i5oI+CCBxoYMsT/JAjCwF5JHINgYNRZxp7hyfyhsJm5A TrgN6ANkFqMOJfU2KX4+HzhiTpzqnYh8wY/zml3sRidyoIzqKYX3E/qQYPkqN/E1WGtoJpXZ0IVyl KCO5FDkg==; Received: from hch by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jtY2d-0004br-7k; Thu, 09 Jul 2020 15:00:51 +0000 Date: Thu, 9 Jul 2020 16:00:51 +0100 From: Christoph Hellwig To: Dan Williams Subject: Re: [PATCH v2 11/12] PM, libnvdimm: Add 'mem-quiet' state and callback for firmware activation Message-ID: <20200709150051.GA17342@infradead.org> References: <159408711335.2385045.2567600405906448375.stgit@dwillia2-desk3.amr.corp.intel.com> <159408717289.2385045.14094866475168644020.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <159408717289.2385045.14094866475168644020.stgit@dwillia2-desk3.amr.corp.intel.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Message-ID-Hash: W2JWMKYHYTSNTDO3K2QLZLIHK5A7K72X X-Message-ID-Hash: W2JWMKYHYTSNTDO3K2QLZLIHK5A7K72X X-MailFrom: BATV+9909843fd9ad822e0971+6164+infradead.org+hch@casper.srs.infradead.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; suspicious-header CC: linux-nvdimm@lists.01.org, Greg Kroah-Hartman , "Rafael J. Wysocki" , Doug Ledford , Jason Gunthorpe , Pavel Machek , Len Brown , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Mon, Jul 06, 2020 at 06:59:32PM -0700, Dan Williams wrote: > The runtime firmware activation capability of Intel NVDIMM devices > requires memory transactions to be disabled for 100s of microseconds. > This timeout is large enough to cause in-flight DMA to fail and other > application detectable timeouts. Arrange for firmware activation to be > executed while the system is "quiesced", all processes and device-DMA > frozen. > > It is already required that invoking device ->freeze() callbacks is > sufficient to cease DMA. A device that continues memory writes outside > of user-direction violates expectations of the PM core to be to > establish a coherent hibernation image. > > That said, RDMA devices are an example of a device that access memory > outside of user process direction. RDMA drivers also typically assume > the system they are operating in will never be hibernated. A solution > for RDMA collisions with firmware activation is outside the scope of > this change and may need to rely on being able to survive the platform > imposed memory controller quiesce period. Yikes. I don't think we should support such a broken runtime firmware activation. _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org